The present progressive is used to talk about what is happening now. It is formed using the formula below:

present indicative conjugation of estar + present participle of verb = present progressive

The present participle (gerund) is usually formed with the stem of the verb plus -ando (for -ar verbs) or -iendo (for -er and -ir verbs). For example: hablar ---> hablando (speaking)

As with Spanish verbs, the are irregular present participles! Verbs of the second and third conjugations for which the stem ends in a vowel, change the ending -iendo to -yendo:

leer --> leyendo

caer --> cayendo

Ella está leyendo su libro.
She is reading her book.

Están (ustedes) leyendo su horóscopo.
You all are reading your horoscope.

The gerund for the verb ir is yendo.

Él está yendo a la escuela.
He is going to school.

Verbs with stem changes:

Those verbs which have the changes o -> ue ->u [e.g., dormir, duermo, durmió] use that u which appears in preterit third-persons forms in the gerund:

dormir --> durmiendo

morir --> muriendo

El abuelo está durmiendo en el sillón.
Grandfather is sleeping in the armchair.

El perro está durmiendo en el piso.
The dog is sleeping on the floor.

Those which have the changes e>ie>i [e.g., sentir, siento, sintió] use that i which appears in preterit third-persons forms in the gerund:

sentir --> sintiendo

Yo estoy sintiendo las garras del gato en mi brazo.
I'm feeling the cat's claws on my arm.

Those which have the changes e -> i ->i [e.g., pedir, pido, pidió] use that i which appears in preterit third-persons forms in the gerund:

pedir --> pidiendo

Nosotros estamos pidiendo un cantante nuevo.
We are asking for a new singer.